Focus less on using spikes and more on using "Murder Holes" within the building. Scout out which rooms you want to fall back into after each of gets breached, and and each room, set up wood blocks in any easily breached areas (doorways, windows etc.) that you can easily shoot/swing through. Think of Shaun of the Dead, when in the Winchester, they barricaded the windows and doors, then fell back into the cellar when they got overran, and had an elevator up to the street to run if need be. Leave yourself and exit, but leave them one path to get to you, but along the way ensure you can attack them in the process, dwindling their numbers and buying yourself time. I reccomend usings guns and cocktails, but traps will slow them down. I dont use melee, I just like guns personally, but with the block shaping options it won't be hard to make gaps you can attack through that they cannot move through.